Smith, who lived through the Great Depression and fought in the British air force during the Second World War, has been a lifelong advocate for the poor.

Online tributes have been pouring in for him as he received treatment in an intensive care unit in Belleville, Ont., after his family said he suffered a fall.

Notables, including Prime Minister Justin Trudeau, actress Mia Farrow and British Labour Party leader Jeremy Corbyn, are among the supporters who have extended their well wishes to the famed activist.

His son John has said on Twitter that his father expressed his appreciation for the support he’s received.

“I told Harry before he fell into a deep sleep about the concern rippling across Twitter for him and he said to me, ‘Tell them, I love each of them so much,’” John wrote on Twitter.

In response, Trudeau tweeted: “Harry’s journey and courage have inspired so much love and kindness on this site, and in the real world too. Thank you for taking us along — we’re pulling for you.”

Smith, who splits his time living between England and Canada, rose to online prominence as a nonagenarian for his progressive polemics rooted in personal strife.

Born in Yorkshire, England, Smith’s four-year-old sister died of tuberculosis in 1926, his family too poor to afford proper medical care before the formation of the National Health Service.

In several books and essays, Smith draws parallels between his own brushes with global crises of the past and current turmoil that affects the marginalized. He was particularly critical of the dismantling of social-welfare systems, the inequities of unchecked capitalism and the rising threat of nationalism.

“I am the world’s oldest rebel,” Smith told UNHCR Magazine in October. “I think there are many things we can do if we put our minds to it, and we shouldn’t be leaving anyone out.”